1. Field of the Invention
The present invention relates generally to a storage and delivery system for a highly viscous material. More specifically, the invention relates to a delivery system which supplies a highly viscous material from a syringe to a catheter or a needle for injection purposes.
2. Description of the Related Art
FIG. 1 shows a prior art device for supplying a fluid to a catheter or needle. The barrel 12 of the syringe 10 has a conical hub 14 formed at an end thereof for dispensing a material 16 stored in the syringe to a catheter or needle 18. The hub 14 is connected to the catheter or needle 18 through a cap 20 which is threadedly attached to the inside portion of an extended portion 21 of the barrel 12. The cap 20 is also cone-shaped and a seal is formed between the two mating conical surfaces of the hub and cap. The seal is tightened by further rotation of the cap 20. This type of device is sometimes referred to as a Luer lock fitting.
The problem with this device is as follows. Prior to the step of attaching the cap 20 to the hub 14, the material 16 may inadvertently contaminate the outer conical shape of the hub 14. In certain applications, the material 16 includes a viscous gel with coarse particles 24 suspended therein such as CoapTite.TM.. The presence of the particles 24 on the conical surface of the hub prevents a tight seal from being formed by the mating conical surfaces of the cap 20 and hub 14. As a result, when the plunger (not shown) of the syringe 10 is actuated to force the material 16 into the catheter or needle 18, some of the gel leaks out through a narrow gap 22 between the conical surfaces of the hub 14 and the cap 20. When this occurs, the relative concentration of coarse particles in the viscous material that travels into the catheter or needle increases, which increases the viscosity substantially. When certain materials are used, the viscosity increases to a level at which the material may not be able to travel through the catheter or needle. That is, even if the force exerted on the plunger of the syringe is increased dramatically, the material cannot be forced into the catheter or needle. Also, this excessive force may damage or break the syringe. If this happens, the catheter/needle delivery system must be replaced, which is expensive, inconvenient and potentially dangerous if the catheter/needle is being used for emergency treatment.
Also, in this prior art device, the end of the syringe where the material is dispensed to the catheter or needle has a reduced diameter A. When the viscous material travels through this reduced diameter portion, the pressure is increased, which further restricts the flow of the material to the catheter or needle.
Further, because the cap 20 is threadedly attached to the hub 14, in order to remove the syringe, it is necessary to rotate the cap 20, which is time consuming and cumbersome.
As an alternative to using screw threads, it is known in the art to utilize a locking slide to secure members in syringe devices. For example, U.S. Pat. No. 2,737,950 (Berthiot) discloses a cooperating lock 18 for securing a needle 10. As shown in FIG. 3 of Berthiot, the lock 18 has a large diameter portion and a narrow diameter portion formed by two web-shaped branches 19. When the needle 10 is moved down towards its operational position, the lower end 14 of the needle passes through the large diameter portion of the lock 18. When the needle reaches its operational position, the lock 18 is pushed so that the groove 20 of the needle is locked firmly into position by the two web-shaped branches 19.
Also, U.S. Pat. No. 5,158,569 (Strickland), discloses a slide plate 84 for securing a catheter 9. As shown in FIG. 3 of Strickland, the slide plate 84 includes a circular opening 94 having a diameter which is greater than the diameter of the catheter 9 and a slot 96 having a width which is less than the diameter of the catheter 9. When the slide plate is in a first, or retracted, position, the catheter 9 passes freely through the circular opening 94 (see FIGS. 4 and 5 of Strickland). When the slide plate is in a second, or inserted, position, the slot 96 frictionally engages the catheter, thereby restraining the catheter 9 in the slide plate 84 (see FIGS. 2 and 6 of Strickland).
When the slide locks disclosed by Berthiot and Strickland are moved to the locked position, these slide locks do not provide any positive indication to the user that the slide locks are properly engaged in the locked position. Therefore, there exists the possibility that the needle 10 and catheter 9 may be improperly secured by the slide lock.